Valve for reverse osmosis purification and storage system

ABSTRACT

A valve for a water purification system operating by reverse osmosis which combines the functions of a pressure control for the blowdown or brine from the reverse osmosis module, and of a pressure control for a purified water container; and also acts as a pressure responsive valve to allow elevated pressure impure water to flow into the purified water container to elevate the pressure of purified water supplied to a dispensing valve when the dispensing valve is opened.

[451 Feb. 26, 1974 VALVE FOR REVERSE OSMOSIS PURIFECATKON AND STORAGESYSTEM [75] Inventor: Donald T. Bray, San Diego, Calif.

[73] Assignee: Desalination Systems, Inc.,

Escondido, Calif.

[22] Filed: Oct. 4, 1972 [21] Appl. No.: 294,965

Related U.S. Application Data [63] Continuation-in-part of Ser. No.284,489, Aug. 29,

Primary Examiner-Frank A. Spear, Jr. Attorney, Agent, or FirmClement H.Allen [57] ABSTRACT A valve for a water purification system operating byreverse osmosis which combines the functions of a pressure control forthe blowdown or brine from the reverse osmosis module, and of a pressurecontrol for a purified water container; and also acts as a pressureresponsive valve to allow elevated pressure impure vate the pressure ofpurified water supplied to a dis- [52] U.S. Cl 210/257, 210/321, 210/43351 Int. Cl. B01d 31/00 water to'flow into the Purified water Containerto [58] Field of Search 210/321, 257, 258, 433 I pensing valve when thedispensing valve is opened. [56] References Cited UNITED STATES P TE TS5 Claims, 4 Drawing igures 3,679,055 7/1972 Wark et al. 2l0/258 X VALVEFOR REVERSE OSMOSIS PURIFICATION AND STORAGE SYSTEM CROSS REFERENCE Thisapplication is a continuation-in-part of my copending application Ser.No. 284,489 filed Aug. 29, 1972.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to a combination valve for controlling water storage pressureconditions and module operating pressure in a reverse osmosispurification and water storage system.

2. The Prior Art Various types of apparatus for storing purified waterproduced by a reverse osmosis system have been proposed and used by theprior art, for example those shown in US. Pat. Nos. 3,493,496;3,568,843; and 3,616,921. These arrangements are useful under manyconditions but do not provide water storage under relatively lowpressure with an accompanying capability for delivery of purified wateron demand at a relatively high or elevated pressure.

It is important to preserve the highest possible pressure drop acrossthe reverse osmosis module so that greatest membrane operatingefficiency is maintained; at the same time water for delivery to adispensing valve or point of use must be at an elevated pressure sincethe valve or faucet location may be remote from the purification unitand ample pressure will be required to provide desired flowto theoutflow point. Thus for a household reverse osmosis system with a waterstorage facility, the purified water pressure in the storage containershould normally not be more than slightly above atmospheric, preferablypsig or so, since more than this will reduce the pressure drop acrossthe reverse osmosis module (the difference between the input householdline feed pressure of the order of 40-100 psig and the purified waterstorage pressure) and result in seriously lowered purificationefficiency and output. While the normal water storage pressure shouldfor this reason be low, output pressure from the storage tank should besufficiently elevated to provide adequate water flow through thedelivery or transfer pipe system to a dispensing valve when this valveis opened, and this pressure may advantageously be of the order of 40 to100 psig more or less.

Operation of previously proposed purified water storage arrangements hasgenerally resulted in a gradual increase in stored water pressure aspurified water has been produced by the reverse osmosis unit and storedin a container. As the pressure of the stored water rises, theefficiency of the reverse osmosis unit decreases because of decreasedpressure drop across the membrane as explained above. Operation ofapparatus according to this invention, however, will result in efficientstorage of purified water at no more than slightly above atmosphericpressure, thus preserving a high pressure drop across the reverseosmosis module for best operating efficiency; while at the same timemaking purified water available on demand from the storage container atan elevated pressure of the order of the original feed line pressure.

SUMMARY OF THE INVENTION My copending patent application Ser. No.284,489

filed Aug. 29, I972 of which this application is a continuation-in-part,describes and claims a water storage and dispensing apparatus for areverse osmosis water purification system. Such apparatus includes astorage container for purified water normally maintained at slightlyhigher than atmospheric pressure connected to a dispensing valve, Whenthe dispensing valve is opened a pressure responsive valve, such as adiaphragm valve, is automatically actuated to supply impure water underelevated pressure, which may be of the order of conventional householdline pressure, to the storage container, thus pressurizing the purifiedwater therein for delivery to the dispensing valve or point of use. Thistype of water purification, storage and dispensing apparatus works wellunder many conditions. It does however require, in addition to thepressure responsive valve, a blowdown back pressure valve or restrictedpassageway flow control to maintain operating pressure in the reverseosmosis module, and also a back pressure valve or restricted passagewayflow control to maintain the slightly above atmospheric pressure atwhich the purified water is normally stored in the storage container.These separate valves or flow control devices are expensive, and often,especially in the case of the blowdown control device for maintainingoperating pressure in the reverse osmosis module, may be occasionallyunreliable in operation due to plugging or partial plugging ofrelatively small diameter flow control channels with particulate matteror foreign material.

Summarized briefly the apparatus of this invention provides a unitaryvalve structure in which all three valves or flow control devices arecombined, and in which possible plugging of the principal blowdowncontrol device is eliminated or substantially reduced. The apparatusincludes means for controlling the pressure of purified water in astorage container, and for controlling the back pressure of brine orblowdown from a reverse osmosis unit or module employed to produce suchpurified water, and also for controlling, by pressure responsive means,introduction of impure water at elevated pressure into the storagecontainer to pressurize the purified water in said container fordelivery to a dispensing valve when the dispensing valve is opened. Thisis accomplished by provision of a body having a first cavity divided bya flexible diaphragm into a pair of chambers, with a plunger assembly onone side of said diaphragm actuated by pressure on the other side of thediaphragm. The plunger opens and closes a port 7 in a second cavity inthe valve body to control flow of impure water (which may include brineor blowdown from the reverse osmosis module) into the storage containerwhen the dispensing valve is opened, and also controls flow of brine orblowdown to disposal means through a restricted passageway in orassociated with the plunger, this restricted passageway also beingconnected to the storage container to maintain and control the storagepressure of purified water contained therein.

BRIEF DESCRIPTION OF THE DRAWINGS Construction and operation of theapparatus of this invention will be more readily understood by referenceto the detailed description thereof and to the annexed drawings inwhich:

FIG. 1 shows a central vertical section of a valve embodying features ofthis invention.

invention in a reverse osmosis water purification and storage system.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to FIGS. 1, 2 and 3,the unitary valve comprises a body 12 in which a first or upper cavity14 is formed as shown by aligned cavity sections in separate top andbottom portions of body 12. Flexible diaphragm 16 divides cavity 14 intoan upper chamber and a lower chamber as shown, the outer edges offlexible diaphragm 16 being sealed to the side walls of cavity 14 byinsertion between the top and bottom portions of body 12, whichportions, together with the interposed diaphragm 16 are maintained intight sealed relationship by through bolts 18 and nuts 20 withconventional washers 22.

At the top of valve body 12 is arranged a connector 24 whichcommunicates interiorly with the top chamber of cavity 14 and which isadapted to receive a connection from the purified water outlet of areverse osmosis module which supplies purified water to a dispensingvalve, as will be hereinafter described in more detail, so that pressurein this line or connection will be transmitted to the top surface offlexible diaphragm 16.

Also in cavity 14, in the bottom chamber thereof and normally contactingthe underside of flexible diaphragm 16 is pressure plate 26 whichprovides a floating plane lower surface for contact with the uppersurface of plunger 28 which rides up and down in a cylindrical secondcavity 30, being sealed to the walls thereof by 0" ring seal 32. Thebottom of cavity 30 is formed with a tapered seat 34 and shoulder 36which is formed as a part of port 38 with which it communicates. Thebottom of plunger is tapered as shown so that its up and down movementwill provide a needle valve control effect between it and the shoulder36 of port 38 with which it mates and can seat.

Plunger 28 is substantially formed with a transverse channel 40 whichcommunicates interiorly with vertical channel 42 which is closed at itsbottom but is open at its top communicating with the central whorl orinnermost convolution ofa spiral groove 44 in its top surface. Thisspiral groove in the top of plunger 28 is illustrated in the enlargedview shown in FIG. 3. When the top of plunger 28 is abuts against theunder surface of pressure plate 26, as shown in FIG. 1, the spiralgroove in the top of plunger 28 becomes closed along its top to form anelongated spiral passageway which is of appropriately small crosssection to provide a restricted passageway for flow control purposes.

A connector 46 is arranged in body 12 communicating with the port 38 inthe second or lower cavity 30 therein, this communication being as shownbelow the shoulder 36. Connector 46 will be connected by a suitable pipeline 48 to the blowdown or brine outlet 50 of a reverse osmosis module52 as will be seen in FIG. 4. Another connector 54 in body 12 will beconnected by a suitable pipe line 56 to brine disposal means such aswaste or sewer, and communicates within body 12 with the bottom chamberof cavity 14. Yet another connector 58 in body 12 communicates with thesecond cavity 30 therein above the seat 34 as shown and will beconnected by a suitable pipe line 60 to the interior of purified waterstorage container 62, the input being fitted with a turbulence reducingbaffle 64 for reasons discussed hereinafter. Valve body 12 mayadditionally be provided with a removable bottom cleanout plug as at 65.Also as will be seen in FIG. 4, feed water inlet 66 in reverse osmosismodule 52 is connected to a source of feed water, which may be amunicipal main or other source of relatively impure water, by a suitablepipe line 68. The purified water from outlet 70 of module 52 flowsthrough a system including a suitable pipe line 72 to dispensing valve74 and a connecting pipe line 76 connects this line with the controldiaphragm 16 through connector 24 in body 12. A connecting pipe line 78connects line 72 with the top of storage container 62. Preferably pipeline 76 is connected to the purified water system at a point close todispensing valve 74.

The purified water produced by module 52 is separated from impure waterintroduced also into container 62 by a pressure transmitting diaphragmor separator, for example by a gradient barrier as at 80. This barriercomprises a narrow layer through which the two types of water diffusevery slowly, the lighter purified water having lower salt content,floating on top of the heavier impure water introduced at a low positionin container 52 through pipe 60 and diffuser 64 which preventsundesirable turbulence. If desired a heater such as at 82 may bearranged to slightly heat the purified water entering the top ofcontainer 62 to insure a greater difference in density and a moresharply defined and stable barrier layer, all as described and claimedin my copending patent application Ser. No. l39,563 filed May 3, 1971.

In operation, the valve of this invention will be connected to functionas described, for example as shown in FIG. 4. When valve 72 is opened todispense purified water the resulting lowered pressure in line 76 willcause diaphragm 16 in valve 10 to lift, thus allowing pressure plate 26and plunger 28 to lift and this allows elevated pressure impure water,introduced into valve 10 through connector 46 from blowdown connector 50of module 52 and originating in feed supply 68, to flow into the bottomof container 62 thus pressurizing the purified water in the containerand the output from valve 74. When purified water is not being dispensedthrough valve 74, the blowdown or brine from module 52 flows into valve10 through connector 46 through port 38, past shoulder 36, thus liftingplunger 28 slightly, then into lower cavity 30 in valve body 12, throughchannels 40 and 42, then through the restricted passageway formed byspiral groove 44 in the top of plunger 28 and the contiguous undersurface of pressure plate 26 and finally out through connector 54. Thepassage between shoulder 36 and the tapered end of plunger 28 could beconsidered a primary flow control in the form of a restricted passagewayfor blowdown or brine entering through connector 46 and the spiralgroove 44 could be considered a secondary flow control. The spiralgroove 44 also acts as the pressure control for purified water incontainer 62 since a small bleed-off through spiral groove 44 is neededto accommodate the purified water entering the top of container 62. Thespiral groove 44 is so sized that this flow plus the primary blowdownflow results in a pressure between the primary and secondary flowcontrol that is slightly above atmospheric. It will be understood thatthe much greater volume of blowdown or brine passing through both of theflow control systems of the valve will result in maintenance of asuitably high or elevated pressure in reverse osmosis module 52, whilethe same spiral groove will maintain a pressure of liquid in container62 only slightly above atmospheric, when no purifled water is beingobtained from dispensing valve 74.

Primary control of blowdown or brine pressure by flow between shoulder36 in port 38 and the adjacent tapered surface of plunger 28 can bebasically or initially adjusted by providing an area ratio between thecross section area of plunger 28 and the area of diaphragm 16 in cavity14. For example, in a preferred embodiment, the cross section area ofplunger 28 may be about one tenth of the area of diaphragm 16 contactedby the liquid in line 76 through connector 24 and the pressures on thesetwo surfaces will be in similar, though inverse, proportion, that is thepressure on plunger 28 will be times the pressure on top of diaphragm16. Thus the pressure in purified water storage container 62 will bemaintained at about 10 percent of the feed line pressure except, ofcourse when dispensing valve 74 is opened. Plunger 28 will float and thespace between its tapered bottom and shoulder 36 will vary toautomatically let more or less liquid flow by to maintain thepredetermined pressure ratio.

The apparatus of this invention is useful to provide a simple reliableand relatively inexpensive combination valve in which all threefunctions of blowdown control, storage container pressure control andpurified output water pressure control can be obtained. The pressureratio between the purified water storage and the module blowdown can bepre-set at a desired value. The primary blowdown control comprising atapered plug seating in a shoulder is less likely to plug since if anysaid purified water therein for delivery to said dispensing valve, theimprovement which comprises; a unitary valve for controlling the releaseof blowdown from said reverse osmosis module, for controlling the normallow pressure in said container, and for controlling introduction ofimpure water into said container, said unitary valve comprising:

a. a body;

b. a flexible diaphragm dividing a first cavity in said body into a pairof chambers, said diaphragm being sealed to the sidewalls of saidcavity;

c. a connector, for connection with the system supplying purified waterto said dispensing valve, communicating with one of said chambers insaid first cavity in said body;

d. a connector, for blowdown disposal from said reverse osmosis module,communicating with the other of said chambers in said first cavity insaid body;

e. a plunger actuated by said flexible diaphragm, the

bottom of said plunger mating with a port in a second cavity in saidbody;

f. a connector, for connection with an impure water supply,communicating with said port in said second cavity in said body; and,

g. a connector, for connection with said container, communicating withthe said second cavity in said body and communicating thereby with saidconnection for blowdown disposal through a restricted passagewayassociated with said plunger and leading to said first cavity in saidbody.

2. A valve according to claim 1 in which the cross section area of saidplunger is a small fraction of the area of said flexible diaphragm.

3. A valve according to claim 1 in which the cross section area of saidplunger is about one-tenth the area of said flexible diaphragm.

4. A valve according to claim 1 in which the top surface of said plungerhas a spiral groove in its top surface which abuts against the undersurface of a pressure plate, which abuts against the under side of saidflexible diaphragm, to form an elongated restricted passageway.

5. A valve according to claim 1 in which the bottom of said plunger istapered to mate with a shoulder in the sidewall of a port communicatingwith said second cavity in said body.

1. In a water purification system in which purified water from a reverseosmosis module is stored in a container at relatively low pressure and,when a dispensing valve connected to said container is opened, impurewater is introduced into said container to pressurize said purifiedwater therein for delivery to said dispensing valve, the improvementwhich comprises; a unitary valve for controlling the release of blowdownfrom said reverse osmosis module, for controlling the normal lowpressure in said container, and for controlling introduction of impurewater into said container, said unitary valve comprising: a. a body; b.a flexible diaphragm dividing a first cavity in said body into a pair ofchambers, said diaphragm being sealed to the sidewalls of said cavity;c. a connector, for connection with the system supplying purified waterto said dispensing valve, communicating with one of said chambers insaid first cavity in said body; d. a connector, for blowdown disposalfrom said reverse osmosis module, communicating with the other of saidchambers in said first cavity in said body; e. a plunger actuated bysaid flexible diaphragm, the bottom of said plunger mating with a portin a second cavity in said body; f. a connector, for connection with animpure water supply, communicating with said port in said second cavityin said body; and, g. a connector, for connection with said container,communicating with the said second cavity in said body and communicatingthereby with said connection for blowdown disposal through a restrictedpassageway associated with said plunger and leading to said first cavityin said body.
 2. A valve according to claim 1 in which the cross sectionarea of said plunger is a small fraction of the area of said flexiblediaphragm.
 3. A valve according to claim 1 in which the cross sectionarea of said plunger is about one-tenth the area of said flexiblediaphragm.
 4. A valve according to claim 1 in which the top surface ofsaid plunger has a spiral groove in its top surface which abuts againstthe under surface of a pressure plate, which abuts against the underside of said flexible diaphragm, to form an elongated restrictedpassageway.
 5. A valve according to claim 1 in which the bottom of saidplunger is tapered to mate with a shoulder in the sidewall of a portcommunicating with said second cavity in said body.